The Yamaha YZ250FX is Yamaha's cross-country and off-road version of the YZ250F, with a wide-ratio six-speed, electric start, an 18-inch rear wheel and a side stand. This page puts the numbers owners look up most in one place: oil, spark plug, valve clearances, coolant, tires, chain and sprockets, and the full spec sheet for the current bike.
All maintenance figures below come from Yamaha's own YZ250FX Owner's Service Manuals, and the 2025-2027 specs come from Yamaha's published specifications. Always double-check against the manual for your exact model year before you wrench, because Yamaha can change specs between years.
Which YZ250FX Do You Have?
The specs split into two generations:
- 2021-2024: The previous generation. The maintenance specs in this guide come from Yamaha's 2021 and 2024 Owner's Service Manuals, and the key figures match across both years.
- 2025-2027: A new generation with a redesigned aluminum frame based on the YZ250F, engine updates (new piston, revised cams and intake), traction control adjustable through Yamaha's Power Tuner app, and a 2.1-gallon tank. Yamaha carried the 2025 design over for 2026 and 2027.
Engine and Maintenance Specs (2021-2024)
| Item | Spec (2021-2024) |
|---|---|
| Engine oil | Yamalube or equivalent, SAE 10W-40, 10W-50, 15W-40, 20W-40 or 20W-50; API SG or higher, JASO MA |
| Oil quantity, oil change only | 0.73 L (0.77 US qt) |
| Oil quantity, with filter change | 0.75 L (0.79 US qt) |
| Oil quantity, engine rebuilt (dry) | 0.95 L (1.00 US qt) |
| Oil filter | Cartridge type |
| Spark plug | NGK LMAR8E-J |
| Spark plug gap | 0.6-0.7 mm (0.024-0.028 in) |
| Valve clearance, intake (cold) | 0.12-0.19 mm (0.0047-0.0075 in) |
| Valve clearance, exhaust (cold) | 0.17-0.24 mm (0.0067-0.0094 in) |
| Coolant capacity | 0.93 L (0.98 US qt) |
| Idle speed | 1,900-2,100 rpm (engine warm) |
| Fuel | Unleaded, 95 RON (E10 acceptable) |
| Fuel tank | 8.2 L (2.2 US gal), including 2.0 L reserve |
| Battery | 12 V, 2.4 Ah |
Source: Yamaha YZ250FX Owner's Service Manuals (2021 and 2024). Check the valve clearances and idle speed with the engine cold and warm respectively, as the manual specifies.
Chassis, Tires and Drivetrain (2021-2024)
| Item | Spec (2021-2024) |
|---|---|
| Front tire | 80/100-21 51M, tube type |
| Rear tire | 110/100-18 64M, tube type |
| Tire pressure (cold) | 15 psi (100 kPa) front and rear |
| Drive chain | 520 sealed, 114 links |
| Stock sprockets | 13T front, 51T rear (3.923 ratio) |
| Chain slack | 50-60 mm (1.97-2.36 in), bike on a stand |
| Fork oil | Yamaha Suspension Oil S1, 501 cm³ per leg (2024 manual) |
Source: Yamaha YZ250FX Owner's Service Manuals (2021 and 2024).
2025-2027 YZ250FX Specs
| Spec | 2025-2027 YZ250FX |
|---|---|
| Engine | 250cc liquid-cooled DOHC 4-stroke, 4 titanium valves |
| Bore x stroke | 77.0 mm x 53.6 mm |
| Compression ratio | 13.8:1 |
| Fuel delivery | Mikuni fuel injection, 44 mm |
| Transmission | Wide-ratio 6-speed, multiplate wet clutch |
| Front suspension | KYB spring fork, fully adjustable, 11.8 in travel |
| Rear suspension | KYB shock, fully adjustable, 12.0 in travel |
| Brakes | 270 mm front disc, 240 mm rear disc |
| Tires | Dunlop Geomax MX33: 80/100-21 front, 110/100-18 rear |
| Seat height | 37.6 in |
| Wheelbase | 57.9 in |
| Ground clearance | 13.0 in |
| Fuel capacity | 2.1 gal |
| Wet weight | 243 lb |
| MSRP | $9,099 (2027) |
Source: Yamaha Motor USA specifications. 2027 pricing from Yamaha's 2027 lineup announcement. MSRP excludes destination and dealer fees.
Maintenance numbers for 2025 and newer: The newer bike has a different tank, chassis and engine internals, so don't assume the 2021-2024 oil, coolant and valve figures carry over. Yamaha publishes them in the Owner's Service Manual that ships with the bike, and you can also buy it from Yamaha's manual store. Tire sizes are unchanged, and the bike still uses a 520 sealed O-ring chain.
The Parts You'll Buy Most
These are the consumables every YZ250FX owner goes through. Confirm fitment for your model year before you order.
Spark Plug
NGK LMAR8E-J
The spark plug Yamaha specifies for the 2021-2024 YZ250FX. Cheap enough to keep a spare in your riding bag.
Check Price →Engine Oil
Yamalube 10W-40
Yamaha's own 4-stroke oil in the grade listed first in the manual. One quart covers a filter change with some left over for top-ups.
Check Price →Oil Filter
YZ250FX Cartridge Oil Filter
Change it with every oil change or every other one, depending on how hard you ride. Pick by model year.
Check Price →Chain and Sprockets
520 Chain and 13/51 Sprocket Kit
Replace the chain and both sprockets together. Stock gearing is 13/51 with a 114-link chain.
Check Price →Setup Tips for the YZ250FX
Sag
The FX is built for off-road use, so most riders set it up a little softer than a motocross bike. MotoSport's published baseline for the 2025 YZ250FX is about 100-110 mm of rear rider sag. Use our sag setup tool to measure yours, and check your owner's service manual for Yamaha's recommended range for your year.
Gearing
Stock gearing is 13/51 on the 2021-2024 bikes. Going up a tooth or two on the rear helps in tight, technical woods, while dropping a tooth or two on the rear gives you more top speed for open desert or GNCC-style riding. Run the numbers in our gearing calculator before you buy sprockets, and see our chain and sprocket guide for when to replace them.
Tire Pressure
Yamaha's spec is 15 psi front and rear. Plenty of off-road riders go a little lower for traction on roots and rocks, but that raises the risk of pinch flats with tubes. Our tire pressure guide gives terrain-by-terrain starting points, and our tire rankings cover the best replacements for the stock Dunlops.
FAQ: Yamaha YZ250FX Specs
How much oil does a YZ250FX take?
On a 2021-2024 YZ250FX, Yamaha specifies 0.75 L (0.79 US qt) with a filter change and 0.73 L (0.77 US qt) for an oil change without the filter. For 2025 and newer, check the owner's service manual for your model year, since the engine was updated.
What spark plug does a YZ250FX use?
Yamaha specifies the NGK LMAR8E-J for the 2021-2024 YZ250FX, with a gap of 0.6-0.7 mm (0.024-0.028 in).
What tire pressure should I run on a YZ250FX?
Yamaha's recommended cold pressure is 15 psi front and rear. Many off-road riders adjust from there based on terrain, going slightly lower for traction in rocks and roots and staying at or above spec where pinch flats are a risk.
Bottom Line
Bookmark this page for your next oil change, plug swap or valve check. For a 2021-2024 YZ250FX, the numbers above come straight from Yamaha's manuals. For a 2025 or newer bike, use the spec table here for the big picture and your owner's service manual for the maintenance figures. And before you put the bike away for the season, run through our winter storage guide.